Secondary battery.



PATBNTBD MAY 7,1907'.

LLYNDON, SECONDARY BATTBRL APPLIUATION FILED JUNE a, 1906.

srrirs fmt LAMAR LYNDON, QF NEW YORK, i\'. Y.

SECONDARY BATTERY.

Specification of Letters Patent.

earner ersten.

Patented May 7, 1907.

Application filled June 3,1905. Serial No. 263,551.

Be it known that I, LAMAR LYNnoN, a citi zen oi the ifnited States, aresidentof the boirough of Manhattan, city, county, and State of NewYork, have invented certain 'new and use'i'ul improvements in Envelopsfor Electrodes, oll which the following is a specihcation accompanied bydrawings.

object oi this invention is to provide an enveiop through which'electrolyte may Another object is to cause a more uniform distributionoi" electrolytic or electro-chem ical action over the surface of theelectrode.

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Another object is to .reduce the height of the containing cell or inwhich the electrodes and electrolyte are placed'. I

Electrodes in storage batteries consist, usually, 'oi a supporting andconducting struc. ture to which the active material is attached.

T he continued use olI the electrodes results. in a loss ei part of thismaterial. lSome of it llalres oil' in particles oi" appreciable size,but .most o'l' the loss comes from the carrying away oi the material inextremely iine particles held in suspension by the electrolyte: hissuspended material gradually settles down at the bottoni oi' the cell orjar in which the ehi'lptrodes and electrolyte are contained7 and iormthe well-known mud orI sediment w iich is observable in storagebatteries after protracted use. This sediment is a conductor andtherefore will short circuit the electrodes oi" opposite polarity ii asullicient amount of it accumulates to bring its level` up high enoughto touch the lower edges oli the electrodes. lt has tlierei'ore beennecessary to frequently remove the electrodes irom the containing vesseland wash out the accumulated sedimentto prevent the possibility of thisshort eircuitmg. lit has also been necessary to malte high supportingribs in the bottoni oi the cell for the plates to resiy on or to suspendthe plates Vl'roni the top oi the cell, leaving in either cese aconsiderable space between the bottom oi the cell and the lower edge oi"the plates, giving room lor the sediment to accumulate without touchingthe plates. Also he active inaterial which is carried oil' from lc-fs inbattery capacity. if the material ine electrodes represents acorresponding should be retained in position thelii'e oi' the batterywould be greatly increased and the Ycapacity better maintained.

l am aware that numerous i'orms ol` envelop have been tried, comprisingperforated rubber and Celluloid, cloths specially treated to resist thedestructive action ol' the electrolyte (pyroxylin)l and the like, which`have somewhat improved the life of battery electrodes, but none has yetbeen produced `which allows free passage of thel electrolyte butrestrains the passage of particles held in suspension.

Certain ty es of' battery plates have been made up witli porousdiaphragme as an integral part of the electrode but the edges of thediaphragms on opposite faces of the electrode were not sealed togetherand loosened particles of the material could pass out at the narrowopenings at the edges.

Primarily; my invention consists oi' two thin diaphragms of porousniarterial-preferable coarsegrainedwood-unitedat the sides and loweredge by a hard rubber or celluloid framework the whole forming a thm boxwhich may be slipped over' the plate. lll the upper edges of the box beabove the surface of the electrolyte, it is unnecessary to seal the top,in this case the electrolyte can only pass to or from the electrode,throughthe pores of the diaphragm. Unless the wood, or other materialused ior making the diaphragm, has. very large pores, no particles ofthe active material can iind their way through the diaphragms and'therefore no loss active material can take place and the aceumu.

lation ol sediment in the cell is prevented.

Figures l, 2 and f5 show apreierred form. l) and D Fig. v1 are sheets'of porous wood. F, F. is a frame oi hard rubber, celluloid or similarmaterial, being iii ell'ect a box having its ia'ces cut away to leaveopenings extending almost across from edgev to edge, sullicient stockbeing lelt to overlap the wooden sheets. Fig. 3 shows this l'rame inperspective. 1n assembling, one diaphragm D is slipped into the lramethen the plate and lastly the diaphragm, l). Fig. 1 indicates thearrangement oi the envelop made in this manner, and Fig. 2 is a sectionthrough a plate covered by this 'form oi envelop.

Another method ol making up this envelop is shown in Fig. 5. lt. it. isan endless piece of elastic material g. rubber,-hav ing a slitl cut inthe proper place l'or the terminal T oi" the plate to pass through.-'llie lOO diaphragms D and D-D only being visible tions and equivalent-sI claim as my invenin the ligure-are laid against opposite faces ofthepllate and the elastic band or channel It. ltr-ot' which Fig. (S is across sectional view-is stretched around the edges of the plate anddiaphragms, holding the latter well against the plate and cllectuallysealing the envelop at its edges.

Obviously an envelop; such as herein shown and described, by preventingthe disintegration and separation o'l' the active material, prevents theaccumulation oll sediment in the bottom of the containing cell andtherefore admits of the use of a shorter jar or containing vessel.

Wood has been s )ecilied as the rel'erable material for the porousdiaphragm. 'lhe most conspicuous reasons for its superiority are (l)cheapness (2) ease of renewal (il) lightness (4) it is thinnerforrequired strength and toughness than any other material (5) it iselastic'to a certain extent and is not fragile (6) it does not containmetallic impurities l(7) thc sheets may be manufactured with com1.aratively little preparation. The wood may betreated to better resistthe action of the electrolyte and an additional protecting covering ofperforated rubber, Celluloid or the like may be used in conjunction withthis envelop if desirable. Obviously no additional separators arerequired when battery plates are incased in these envelops.

While this forni of envelop is particularly adapted for storage batteryelectrodes it may be used for a variety of other purposes.

Obviously this invent-ion may be embod/ied inl Widely varying formstherefore wit-hout limitingthe invention to the constructions shown anddescribed nor enumerating varial. An envelop for storage batteryelectrodes comprising two porous diaphragnis of vegetable mattei', onebeing laid against either face of the electrode, in contact with theactive material thereof, theedges ofthe diaphragl'ns being so closed upas to exclude the passage of electrolyte to the electrode, exceptthrough the pores of the said diaphragm, and an unbrolten and imperviousllexible elastic acid resisting framework surrounding at least threeedges of the said electrode, whereby the diaphraglns are held inposition and sealedat the surroundet'l edges.

'2. -\n envelop for storage battery electrodes, comprising two porousdiaphragms otv vegetable matter, one being laid against. each face ol"the electrode in contact with the active material`thereof. t'he edges ofthe dia- .phragms being inclosed in a flexible elastic frame to excludethe 'passage of electrolyte to the electrode, except through the poresof the `said diaphragm. u

3. An envelop for storage battery electrodes, comprising two porousdiaphragms of vegetable matter, one being laid against each face of theelectrode in contact with the active *material thereof, the four edges'of the diaphragme being 4inclbsed in acontinuous flexible yrubber framestretched over the-diaphragm to exclude the passage of electrolyte tothe electrode except through the pores of the said draphragin.

LAMAR LYNDON.

Witnesses H. CuITTEMoRis, R. B. MARTEN.

